Compared with Thomas & Skinner laminations the prices for Alpha c-cores are not that bad.
Alpha c-cores come in M4-011 grain oriented silicon steel, which is already better for audio transformers than M6-014.
And, not unimportant for DIY, there is no minimum order quantity for Alpha cores.
Please note that I have no connection with Alpha cores, and I don't have experience with their cores.
Alpha c-cores come in M4-011 grain oriented silicon steel, which is already better for audio transformers than M6-014.
And, not unimportant for DIY, there is no minimum order quantity for Alpha cores.
Please note that I have no connection with Alpha cores, and I don't have experience with their cores.
Tony,
That Bridgeport tranny link is what I have been looking for now for about a month. The C core 500 va is only 27.00 dollars. I can handle that. Now to do some math and get out my credit card. They use high quality materials and stock a wide variety of common sizes.
I never really wanted to use the EI type platform it was just something I thought would be easier to source == until now.
Will have to rig something up on my drillpress to turn the bobbins. A guy in Singapore places a thin layer of fine wire between the bobbin and inner support which he then just pulls out to get the bobbin off the turning jig support. I thought that was a truly neat idea.
One of the tricky parts in this winding thing is when to use the reverse hand wind. Not all of the wraps go in the same direction. This is something I saw on the MC3500 schematic.
I got my 12 GU50 tubes Thursday. Now to find some nice bases. I really like the Russian cage base it looks cool and different. I plan to light up the living room at Christmas this year with some nice tube amp glow. May get a little heat to boot. That is roughly 9 months. Should be enough time to get one amp right without too much smoke. Maybe!!! Very noob to this.
It is a beautiful pre-spring day here in Georgia with the hot air balloons flying over the house. Ya'll enjoy Tad
That Bridgeport tranny link is what I have been looking for now for about a month. The C core 500 va is only 27.00 dollars. I can handle that. Now to do some math and get out my credit card. They use high quality materials and stock a wide variety of common sizes.
I never really wanted to use the EI type platform it was just something I thought would be easier to source == until now.
Will have to rig something up on my drillpress to turn the bobbins. A guy in Singapore places a thin layer of fine wire between the bobbin and inner support which he then just pulls out to get the bobbin off the turning jig support. I thought that was a truly neat idea.
One of the tricky parts in this winding thing is when to use the reverse hand wind. Not all of the wraps go in the same direction. This is something I saw on the MC3500 schematic.
I got my 12 GU50 tubes Thursday. Now to find some nice bases. I really like the Russian cage base it looks cool and different. I plan to light up the living room at Christmas this year with some nice tube amp glow. May get a little heat to boot. That is roughly 9 months. Should be enough time to get one amp right without too much smoke. Maybe!!! Very noob to this.
It is a beautiful pre-spring day here in Georgia with the hot air balloons flying over the house. Ya'll enjoy Tad
TNX for interest.
Prefer the last version:
http://www.dissident-audio.com/OPT_da/PST-and-OPT.tar.gz
Simply extract the archive in a new folder and go.
No installation needed, no garbage in your registry.
Works also with Linux + Wine.
A PSU transfo calculator as a bonus (sorry, French speaking . . . but so few words).
Have fun, if you don't like it just delete the folder, nothing to "uninstall".
Yves.
Speaking on bifilar how do manufactures like Mcintosh, who has a history of there equipment lasting several decades, cope with several hundred volts of potential between primary and secondary side by side. I do not know of any equipment designed that reliably performs, with this degree of potential difference, on the wire varnish alone.
When I get my core order from Alpha I would very much like to use multifilar winding. It just seems to be the best way to combat capacitive elements in the transformer. The higher impedance, cheaper, sweep tubes would benefit from this arrangement. KT 88 and family are too expensive for me to experiment with.
I just read the transformer thread where BudP was praising the standard silicon core over the amorphous. The potential difference is not worth the added expense. Good silicon C cores for less than 20.00 each.
I plan to wind with two C cores like the Mac's use. It also is easier to band with a nice stainless steel hose clamp. You do not have to insert between the winding and core.
PieterT thanks in hindsight. Tad
When I get my core order from Alpha I would very much like to use multifilar winding. It just seems to be the best way to combat capacitive elements in the transformer. The higher impedance, cheaper, sweep tubes would benefit from this arrangement. KT 88 and family are too expensive for me to experiment with.
I just read the transformer thread where BudP was praising the standard silicon core over the amorphous. The potential difference is not worth the added expense. Good silicon C cores for less than 20.00 each.
I plan to wind with two C cores like the Mac's use. It also is easier to band with a nice stainless steel hose clamp. You do not have to insert between the winding and core.
PieterT thanks in hindsight. Tad
Tad, be aware that multifilar windings "combat" capacitive elements just be fully utilizing capacitive coupling; that only works in your favour with 1:1 ratios (like McIntosh did in their unity coupling output transformers with equal bifilar wound plate and cathode windings).
We could keep on discussing core materials.
Fact is that amorphous core transformers are offered by companies (Tamura, Lundahl, me) being the best they have. It would not make sense to offer these when feedback from customers would not confirm their superiority
Amorphous core transformers are more expensive than their silicon steel brothers because these cores are more expensive; however the total cost is mostly determined by the time involved (winding, finishing).
I know beforehand that the following remark will cause a problem but. There are numerous accounts proven by Rod Elliot and confirmed in Morgan Jones book that what people hear as improvement cannot be substantiated in properly conducted blind A to B testing. The world is full of a multitude of varying individuals who will attest to what they have is always the best and others that say the more expensive items will always be better. I for one have very poor hearing and a very limited amount of very hard earned money. I choose to rely on people like those on this forum my own ears and of course what I can afford as being better. At least for me.
I am in agreement that the data, using thinner lams and better steel, supports the amorphous argument but, these same people will spend 1000.00 a foot on speaker cable. Just look at John Curl's Blowtorch preamp. It is a mess of spiderweb wiring and yet costs what a small house does. Go figure.
I trust the very good advice I get from you members and try to adhere to something I call logic not having the empirical knowledge to test things myself. I love all Mcintosh equipment yet it gets a bad rap for overuse of feedback. I would love to build my transformers with the amorphous steel I just think a good design with standard high silicon is more practical. Will I hear a difference, probably not, but I will be proud if things do not smoke.
I do not even listen to music much I just like to make things from scratch. It is the accomplishment not the music and the fact that individuals with very in depth knowledge of this field will even respond to my questions. I very much appreciate all of the good information this thread is provided. It is something we do not get into very often.
It is time to rig up a winding thing. This is going to be fun. Tad
I am in agreement that the data, using thinner lams and better steel, supports the amorphous argument but, these same people will spend 1000.00 a foot on speaker cable. Just look at John Curl's Blowtorch preamp. It is a mess of spiderweb wiring and yet costs what a small house does. Go figure.
I trust the very good advice I get from you members and try to adhere to something I call logic not having the empirical knowledge to test things myself. I love all Mcintosh equipment yet it gets a bad rap for overuse of feedback. I would love to build my transformers with the amorphous steel I just think a good design with standard high silicon is more practical. Will I hear a difference, probably not, but I will be proud if things do not smoke.
I do not even listen to music much I just like to make things from scratch. It is the accomplishment not the music and the fact that individuals with very in depth knowledge of this field will even respond to my questions. I very much appreciate all of the good information this thread is provided. It is something we do not get into very often.
It is time to rig up a winding thing. This is going to be fun. Tad
That is not true IMHO.
OK, there are always people buying the most expensive stuff, maybe just to feel "happy", or to impress the neighbour, or out of ignorance.
In tube amplifiers the output transformer is a vital part; at the same time differences between quality transformers are, and should be, subtle. When you're looking for quality it does make sense to pay attention to this (but you already do). Unlike tubes, output transformers can last a life time, and good quality transformers are always a good investment.
When these will be your first transformers, I would advice to use silicon steel anyway.
Some time ago I had a MC275 on loan; a good amp but actually, and a bit to my disappointment, nothing "special", not quite what I expected as I was especially interested in the unity coupling design.
At the same time I dismantled a shorted MC275 output transformer and so I was able to check winding ratios. It became clear that the MC275 is a design applying all "tools" to get the most power out of a pair of KT88's: cathode feedback in the output stage, therefore requiring additional gNFB. Huge voltage gain in input and driver stages because the power stage has little gain. Lowish primary impedance of the output transformer, a.s.o. Result IMHO is an amp with power and decent specs but not a champion in refinement; I'd say for a tube amp it is a real power horse.
When you want to make something McIntosh like, try to improve on the design; it is not that difficult.
I indicated before, but take a look at Hugh Alvin Lockhart's design of the same principle, designed at about the same time, improving on some important things, especially primary impedance of OPT and an elegant driver stage (6SN7 - interstage transformer) which gives the required voltage swing without all the MC275 tricks. When you succesfully wind the opt's, the interstage transformers are a "gimme". Lockhart even shows winding schemes (using c-cores, yess!!).
That was my first question where is the link thanks.
I hAve not listened to a tube amplifier since way back in my childhood. I hope this current venture is successful. I plan to copy a design by Chrisl Ludwig in Germany. It seems he has done all of the necessary work for a nice build.
I would like to know if using a cascode in the frontend would make for a better amp than a straight differential layout. He has offered both on his website. A few remarks from Morgan Jones is that the ECC88 is the only tube made explicitly for cascode and the ECC83 used in Christl circuit may be troublesome.
Any comments? The website also offers up the full winding layout for the power and output transformers. I can only think that any individual who has put this much work into a hobby project has done all of his homework. I do not have the knowledge or skills to design something like this. I guess with a bunch of free time I could eventually succeed. The time is just not there.
Anyone ever wondered why the winding gurus never give up the arcane secrets inherent in this craft. There are a plethora of good site with calculations and such but no sites with the trial and error factor. From what I have discovered there are numerous winding layouts some better than others. There is also a site where the wind is vertical. It is supposed to produce extremely high frequency output with a minimal distortion. No specifics!!!
In response to the tube impedance I was referring to the GU50 which is rather high.
I hope my C core get here this week. This is a physical project, something I can get my hands on, where the effort is not headache producing. Kind of like physical therapy.
I have just finished laying out the vegetable garden with Diana Krall blasting for the neighbors in the backyard. The Leach really is good at this. Long live the the man in his achievements. If this tube amp is anywhere as good as the Leach I will be one happy amp builder.
Tad
I hAve not listened to a tube amplifier since way back in my childhood. I hope this current venture is successful. I plan to copy a design by Chrisl Ludwig in Germany. It seems he has done all of the necessary work for a nice build.
I would like to know if using a cascode in the frontend would make for a better amp than a straight differential layout. He has offered both on his website. A few remarks from Morgan Jones is that the ECC88 is the only tube made explicitly for cascode and the ECC83 used in Christl circuit may be troublesome.
Any comments? The website also offers up the full winding layout for the power and output transformers. I can only think that any individual who has put this much work into a hobby project has done all of his homework. I do not have the knowledge or skills to design something like this. I guess with a bunch of free time I could eventually succeed. The time is just not there.
Anyone ever wondered why the winding gurus never give up the arcane secrets inherent in this craft. There are a plethora of good site with calculations and such but no sites with the trial and error factor. From what I have discovered there are numerous winding layouts some better than others. There is also a site where the wind is vertical. It is supposed to produce extremely high frequency output with a minimal distortion. No specifics!!!
In response to the tube impedance I was referring to the GU50 which is rather high.
I hope my C core get here this week. This is a physical project, something I can get my hands on, where the effort is not headache producing. Kind of like physical therapy.
I have just finished laying out the vegetable garden with Diana Krall blasting for the neighbors in the backyard. The Leach really is good at this. Long live the the man in his achievements. If this tube amp is anywhere as good as the Leach I will be one happy amp builder.
Tad
Vacuum impregnating transformer windings
Since this is a fanatical audio site would it be worthwhile to vacuum impregnate the transformers after winding. I live in an area with very high humidity which of course is going to be in the windings. I know that some of my power transformers have developed a hum and higher heat when I first pot them. Most of the time this goes away.
I have a nice vacuum pump salvaged from a military poisonous gas device. It should not be too hard to get all of the moisture out of the transformer before applying epoxy or wax.
I have also sourced some nice thin teflon film for interwinding insulation.
Tad
Since this is a fanatical audio site would it be worthwhile to vacuum impregnate the transformers after winding. I live in an area with very high humidity which of course is going to be in the windings. I know that some of my power transformers have developed a hum and higher heat when I first pot them. Most of the time this goes away.
I have a nice vacuum pump salvaged from a military poisonous gas device. It should not be too hard to get all of the moisture out of the transformer before applying epoxy or wax.
I have also sourced some nice thin teflon film for interwinding insulation.
Tad
hey Tad, i use air dying polyurethane electrical varnish, that i buy in liter cans.....
my completed traffos are immersed completely in a tub full of varnish, until all bubbles are gone, then i hang them under the sun to dry....takes more than a day to dry....
i repeat the process at least twice.....
my completed traffos are immersed completely in a tub full of varnish, until all bubbles are gone, then i hang them under the sun to dry....takes more than a day to dry....
i repeat the process at least twice.....
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